Hydraulic opening and closing device



Nov. 13, 1934. E. ENGEL 1,980,617

HYDRAULIC OPENING AND-CLOSING DEVICE Filed Oct. 26. 1931' INVENTOR Srnst grzyel ATTORNEY Patented Nov. 13, 1934 HYDRAULIC OPENING AND CLOSING DEVICE Ernst Engel, Frankfort-on-the-Main, Germany,

minor to Alfred Teves Company, Frankforton-the-Main, Germany Application October 26, 1931, Serial No. 571,148 In Germany May 30, 1931 6 Claims.

This invention deals with a hydraul c door opening and closing mechanism which is especially adapted to operating folding doors on vehicles, and difl'ers from similar arrangements heretofore used in providing in each main drive cylinder, one of which is used for opening and the other for closing the doors, a piston with a smaller cylinder and another piston therewithin,

so arranged that as well upon opening as on closing, each movement of the leaves of the door is started by the small cylinder and completed by the large cylinder. Thus the dead center positions which the door sections occupy at the beginning of each movement, and their inertia, are It overcome by the exertion of greater force during this portion of the movement, while during the remainder of the door movement, when less power is required, the motivation is by the larger cylinder and is accordingly more rapid.

Another important object of the invention is the provision of a double acting fluid motor mechanism of improved construction and incorporating a novel arrangement whereby greater force and slower travel are effected at the beginning of each movement in each direction, while faster travel under the application of lesser driving force is derived during the latter part of each movement.

Other objects and advantages will be apparent from the following description, wherein reference is made to the accompanying drawing illustrating a preferred embodiment of my invention.

The single figure of drawing illustrates somewhat diagrammatically an exemplary embodi- 5 ment of the invention:

The opposed pressure-producing cylinders, which are operated through the lever 1 (shown fulcrumed at 2) and the rod 3, consist each of one interfltting cylinder pair, the cylinder assembly on the right in the drawing being for opening and that on the left for closing. The large opening cylinder 4 contains the large piston 5, which is itself formed with a small cylinder 6 therein within which is slidable a smaller piston 7. For closing there is provided a similar assembly comprising a larger cylinder 8 with piston 9, which again contains a small cylinder 10 and piston 11. The rod 3 is arranged to actuate either smaller piston when moved to push the same inwardly, but the rod floats between them so that it can pull neither. In pistons 5 and 9 are canals 12 and 13 connecting cylinder 4 with cylinder 6 and cylinder 8 with cylinder 10, respectively. From cylinder 4 runs a fluid pressure transmission line 14 with which is connected a pressure absorbing or motor cylinder 15. Cylinders 8 and 10 are similarly connected by means of a transmission tube 16 with another motor cylinder 1'7. Cylinders 15-17 are also arranged in opposed relation and their pistons 18-19 are Joined by means of a rack 20, which meshes with a gear 21. Gear 21, or its shaft, is arranged to actuate levers 22-23, which by means of links 24-25 are joined to cranks 26-27. The latter are rigidly secured to pintle rods 28-29 about which the folding doors 30-31 swing, their inner leaves being fast upon the rods andtheir outer leaves hingedly joined to the inner.

The mode of operation of the arrangement is as follows:

In the drawing the folding doors 30-31 are shown open. To close them, lever 1 is moved in the direction of arrow a, only the piston 11 being at first moved. The traction on lever 1 now brings pressure on the fluid in cylinder 10. Although its piston surface is small, a correspondingly great fluid pressure results in the cylinder 10. Piston 9 is held against outward movement under the transmitted pressure delivered to cylinder 8 through canal 13 by stops 32, shown carried by the end of the cylinder. The pressure is of course transmitted through the line 16 to piston 19 in cylinder 17, which is forced to the right to actuate the rack 20, gear 21, levers 22-23, links 24-25 and cranks 26-27, and so the doors. Easy mastering of the greater resistance to movement offered by the doors when in the dead center fully folded open position is assured by the great pressure generated in the small cylinder 10 which is then effective. When piston 11 has been moved inwardly into contact with large piston 10, which it may engage by means of flange 34, piston 9 also takes part in the movement, being then directly actuated by continued movement of the lever 1. There results because of the larger piston surface thus made effective and the consequent displacement of a much larger quantity of fluid per degree of movement of the lever 1, a correspondingly quicker movement of piston 19, and thereby more rapid closing of the doors. Despite the fact 100 that the larger piston 10 must be moved during the latter part of the operation, the closing of the door may be accomplished with approximately an equal expenditure of power upon lever 1, as after overcoming the inertia of the door and pass- 105 ing the initial dead center point through the a pressure generated in the small cylinder, only slight power is needed to continue the movement.

During the closing operation, because of connection between piston 18 and piston 19 furnished 110 by the rack 20, piston 18 is also moved, at the same rate as piston 19, and displaces the fluid in cylinder 15, forcing it thru transmission line 14 into cylinder 4, where the other large piston, 5, is moved thereby until it engages stop 33, and then the small piston 7 is moved and alone follows rod 3. Both pistons are thus moved to positions which correspond to the opposite of the illustrated positioning of pistons 91l; lever 1 assuming the dotted position in the drawing. 01 importance in this procedure is the loose connection of the rod 3 with the two pistons 7-11. Thereby the pistons in the cylinders to which returned liquid is being delivered are moved solely by the liquid, instead of drawn by rod 3. This enables movement of the driving pistons more quickly without resulting in moving the opposed driven pistons more quickly than liquid can be delivered to the latter, preventing formation of vacua either between the pistons following rod 3 and the liquid, or anywhere in the system, thereby eliminating the possibility of ai leaking thereinto.

It will be apparent that to open the doors, lever 1 is moved in the direction of arrow b, "and the small piston 7 thus first moved. Again liquid pressure results, now in the opposite direction, which under the influence of the small piston permits easy overcoming of the initial dead center point resulting from the extended position of the folding door members, and their inertia. Then when the small piston contacts stop 35 the large piston 5 continues more quickly the opening of the doors, and the fluid displaced over transmission line 16 similarly returns pistons 9-11 to the starting position ready for another closing operation.

Now having described the invention and the preferred embodiment thereof, it is to be understood thatthe invention is to be limited not to the specific details herein set forth but only by the scope of the claims which follow.

1. In a hydraulic reciprocating system, a pair of opposed fixed driving cylinders, a substantially cylindrical piston in each, asmaller cylinder and piston in eacn of the first mentioned pistons, floating drive means unconnected to but adapted to abut each of the smaller pistons adapted to act compressively thereupon when moved in opposite directions, thereby exerting no tractile effort on one of the smaller pistons when compressively moving another.

2. A hydraulic driving pump comprising a pair of opposed cylinders arranged with their heads outermost, a trunk type piston in each cylinder,

an inner cylinder in each of said pistons, said inner cylinders having opposed inwardly facing open ends an inner piston in each inner cylinder,

said inner pistons being arranged in opposed relation, and means including a single operating lever for compressively moving either of the inner pistons, the interfitted cylinders being interconnected, whereby the pressure within both the outer and inner cylinder of each pair of cylinders may be affected by actuation of the inner piston, the inner pistons being movable outwardly independently of each other.

3. A hydraulic driving pump comprising a pair of opposed cylinders, a trunk type piston in each cylinder, an inner cylinder and piston arranged inside each of said first mentioned pistons, said inner cylinders having opposed inwardly facing open ends said inner pistons being arranged to arranged between said inner pistons to enable selective actuation of either thereof, the thrust member being movable away from each of said inner pistons independently thereof.

5. A hydraulic driving pump comprising a pair of opposed cylinders, a trunk type piston in each cylinder, an inner cylinder and piston arranged inside each of said first mentioned pistons, said inner pistons being arranged substantially opposite and parallel to each other, and a common thrust member arranged between said inner pistons to enable selective actuation of either thereof compressively, said thrust member being functionally unconnected to the opposite piston while compressively moving either thereof.

6. A hydraulic driving pump comprising a plurality of substantially coaxial opposed cylinders arranged with their heads outermost, a piston in each cylinder, an inner cylinder and piston in each of said first mentioned pistons, the inner pistons being arranged insubstantially coaxial opposed relation, and a single thrust element interposed between the inner pistons to enable selective compressive actuation thereof, but unconnected to the opposite piston while compressively actuating either thereof, whereby tractile effort cannot be exerted on either piston by the thrust element.

ERNST ENGEL. 

